Credit card transaction forms are commonly used for business dealings recorded with the use of consumer credit cards. In normal business use, two or more identical copies are made of a single exchange. Each copy generally includes confidential information such as the customer's name, account number and the expiration date of the card as well as other information such as the merchant's name and account number.
Typically, this information is imprinted on the form when sufficient pressure is applied against the form. To make an imprint of the credit card, the form is sandwiched between an embossed customer credit card and a pressure applying roller. The embossed information from the face of the credit card is imprinted on the surfaces of the various plies making up the form. Alternatively, in a point of sale environment where machines read the information encoded on a magnetic strip attached to the credit card, the encoded information which is read by a machine may be transferred to the transaction form by an impact printer, a cash register or a similar machine. In addition, the pressure applied by a hand held stylus is sufficient to make an imprint on each ply of the form.
Several methods of imprinting the information on the plies of the form are routinely practiced. Historically, imprintable bond paper plies of the form were separated by carbon coated tissue paper plies. As a roller moved over a transaction form disposed upon an embossed credit card, pigment was transferred mechanically from the surface of the carbon tissue paper to the bond paper ply. The mechanical transfer of carbon pigment necessarily resulted in a negative image of the imprint being formed on the carbon tissue paper. Careless handling or disposal of the carbon tissue paper with the negative image disposed thereon compromised the security of the imprinted information. Additionally, forms using carbon tissue paper often could be smudged as an individual inadvertently contacted the carbon sheet and transferred the carbon onto other parts of the form or onto the individual's hands or clothing. An example of this type of transaction form is illustrated in U.S. Pat. No. 3,113,516.
More recently, plies coated with colorless, chemically reactive dyes, which produce a visible image when subjected to pressure, have been used to make carbonless transaction forms. The reactive dyes are typically used in a two part system. One part contains a colorless reactive dye and the second part contains agents which initiate the chemical reaction needed to change the colorless dye into a visible dye. An example of a carbonless dye system used in a business form is described in U.S. Pat. No. 3,981,523.
Generally, the back of one ply is coated with the colorless reactive dye and the front of the immediately adjacent ply is coated with the requisite visualizing agents. When the two plies are placed in contact under sufficient pressure, the colorless reactive dye and the visualizing agents react and create an image on the ply coated with the visualizing agent. Generally, no image is desired or observed on the ply surface coated with the colorless dye. If the top face of a top ply of standard carbonless forms is to be imprinted and a visual image is to appear, it must have a coating mix of both the colorless reactive dye and the visualizing agent applied to the top face of the top ply in order to generate a visible image on the top face when it is subjected to sufficient pressure to cause the desired reaction.
These carbonless forms suffer from a number of disadvantages in that they use proprietary dyes and chemicals, require relatively complicated manufacturing machinery and special application processes, and are relatively expensive. It is generally required that, in applications calling for carbonless paper forms, one must purchase bond paper that has been coated with special agents to achieve an image on the top ply. The cost of such coated bond paper is quite high.
The use of a transparent, translucent, semi-translucent or treated semi-translucent top ply on a business form is also practiced in the industry. In known forms, the top read-through ply may be imprinted with an image on the bottom surface of the top ply, the image being made by mechanically or physically transferring pigment from either an adjacent carbon tissue paper ply or from a transferable pigment applied on an adjacent bond paper ply. Unfortunately, in both instances there is an actual, physical transfer of pigment from one ply to another such that both methods of pigment transfer generate an undesired negative image either on the adjacent carbon tissue paper ply or on the adjacent pigmented bond paper ply. An example of a form which provides a negative image on a ply is seen in U.S. Pat. No. 3,981,523. The physical transfer of pigment also creates problems in that there is an increased opportunity for smeared or smudged copies due to inadvertent physical transfer of pigment from one ply to another. In addition, special coatings may be needed on the pigment receiving ply as well as the pigmented bond paper ply which again requires relatively costly application equipment and processes.
What is desired is a transaction form which has the simplicity and security of a carbonless form but which utilizes a translucent top ply on the form as opposed to other expensive top plies such as coated bond paper. It also is desired to have a transaction form which, when imprinted with information from an embossed credit card or transaction card disposed under the bottom ply of the form, yields positive images on both the back surface of the top translucent ply and the top surface of the adjacent ply without the use of carbon black, carbon red, or any carbon pigmented dye. It is further desired to have a carbonless form which does not utilize a coated bond paper on the top ply but which has a top ply that can be produced from generally available, inexpensive translucent paper which may be easily coated with one or more chemically reactive agents without the need for special processing techniques and machinery.